Processing meat such as beef and pork results in a significant amount of trimmings which are comprised primarily of fat. Such trimmings typically have a very low economic value. However, meat trimmings contain portions of relatively lean meat. The desirability of reclaiming these lean portions has been recognized in the prior art. Prior art systems reclaim lean meat from trimmings by grinding and extruding the trimmings and cutting or forming the ground and extruded trimmings into small pieces for subsequent sorting of relatively lean pieces from relatively fatty pieces. Sorting is based upon the colors of the ground pieces.
Such systems have a number of shortcomings. For instance, grinding and extruding the meat tends to mix fat and lean components, making meaningful sorting difficult or impossible. It has also been found that grinding and extruding tends to blur or smear any color distinctions between product types. This makes subsequent optical inspection difficult or impossible, because optical discriminations must essentially be made based upon the average color or shade of the meat pieces.
A further disadvantage of existing methods and systems is that ground meat tends to become sticky or gummy, and to adhere to conveyors which are used to move the meat through processing or inspection stations. This creates a product handling problem and also results in a significant loss of fat as it adheres to support surfaces. Ground meat also tends to clump. Again, this complicates and reduces the efficiency of inspection and sorting. An even further disadvantage of existing systems is that most methods of grinding and extruding generate a very narrow stream of meat pieces. Such a narrow stream makes it difficult to exploit the efficiencies which might otherwise be obtained when using modern high-speed wide-belt optical inspection and sorting systems.
To combat the problems noted above, some prior art systems have resorted to freezing the meat during processing. This helps reduce clumping and color blurring, but can be expensive and inconvenient. Other prior art systems ;have employed vibratory elements or shakers to reduce clumping and to spread ground pieces laterally so that downstream wide-belt sorters can be used to their fullest advantage. However, vibratory elements are disfavored in meat processing plants, primarily because of the difficulty of cleaning them.
The invention described below avoids the noted disadvantages of prior art meat sorting systems. It provides a laterally-distributed high-speed flow of meat pieces for efficient automated inspection and sorting with modern equipment. It does not require freezing the meat and does not require using any vibratory elements.